#include
using namespace std;
#define ll long long
int main()
{
ll m,n;
cin>>m >>n;
ll a[m][n];
for(ll j=0;j<m;j++)
for(ll i=0;i<n;i++)
cin>> a[j][i];
for(ll j=0;j<n;j++)
{
if(j%2==0)
{
for(ll i=0;i<n;i++)
{
cout<<" "<<a[i][j]<<",";
}
}
else if(j%2!=0)
{
for(ll i=(n-1);i>=0;i--)
{
cout<<" "<<a[i][j]<<",";
}
}
}
cout<<" END"<<endl;
}
// not passes all test cases
